Centering device for lathes and the like



July 12, 1960 A. J. VASSELLI CENTERING DEVICE FOR LATI-IES AND THE LIKE Filed Feb. 12, 1958 0 Zi 1 n 7 i W2 w 0 eh 3 2 July 12, 1960 A. J. vAssELLl CENTERING nEvIcE EoR LATHEs AND THE LIKE Filed Feb. 12, 1958 l INV NTOR ANTHONY J: HSSEZL/ M BY ATTORNEY This invention relates'toA a vcentering device to be employed with lathes and the like and particularly to tools which alord to operators of lathes and similar machines the ability `to `cut accuratecylinders of the desired diameter and tapered workY pieces.

. .The device which .is the subject of this'invention -is peculiarly adapted forfuse in'connection with conventional lathes, grinders, millers and similar machines. Generally, the tool providesanadjustable work center for Vthe tail stock of such machines.V A novel featureof the tool' is that it providesmeans for positioning thepce'nter inrtwo planes thus enabling the formation of precisecylinders andtapers andy providing an expedient to compensate forl arnis'alignmentvofthe centers due to aninherentmis alignment in the lmachine which'is .sometimesfpresenjt by.

lreasonV of wear ornamis'use resulting in' anunusualvstress on thehead and tail stocks. Secondly, vprovision is madev forrallowingfthe placement of the tailY stock center on the' work end underrspring pressure'so vthatjthe center can Patented Jury 12, 1960 Fig. 1v1 lis a modification showing the device associated with a gear cutting machine.

vReferring to the drawings, there is provided a conventional lathe 12 having a head stock 13, a multiple speed pulley assembly 14 for driving a head center 15 which holds one end of work piece W', the other end of l the work piece being supported. by lathe device -16 which in turn is carried by thettail stock 17 of the lathe. The tail stock is releasably clamp-ed to the ways by clamping member 18 and is positioned thereon in the usual manner,

. the device beinglongitudinally adjustable by.Y means of hand'wheel 20. The cutting tool 21 conventionallysup-` ported onthe carriage 22 is adapted to be transversely disposed relative'to the Vwork piecetby means of end wheel 23.4.The carriage 'may be longitudinallyfed by power on adjustment of knob 24 or, optionally, the carriage may be caused toV travel by means of hand wheel 25.

' The device 16 has atlower borewhich'receives the cylindrical endof` tail :stock b ar' 26, the otherA end ofrwhich is taperedand received in the Morse tapered openingof the tail stock spindle 2.7, being clamped, therein by mem-ber27a." The housing, 28 for the holder is split in the region of the lower bore and a,` clampingscrew 29 is received in the bifurcated sections jof the casting whichr is adaptedtolocklthe tool on thetail'stock bar 26.vv Ad- ,t ditionally, the housing 2S'is provided with anup'per bore n which-isfbacked byaplate. and receivesfa cylindrical sleeve 3.1having -an irregularopening`-31a vformed therein as shown in Figl 10 The housing 28 Vis similarly split be locked in position while it is in pressure contact lwith` the .work Ys o asY to preventwobbling 'or'run outtofjthe` work on Ithe tailstck center during operation. By proper' ySpring :selectiomit is possible to pred'eterminethe` desired rotative pressure exerted by the work against the'center.

proximateth'e'upper-'boreand'a bolt 29a through the l, split sections serves to lock'the sleeve 31to theV housing." A'clanip-ESZ isl disposed in' a threaded 'hole in thehbusing; l ZSlandfhas atapered fend 33 which is received in the region of the opening l31a whereinthere is cut or formed an, arcuate"(wall 'section33a which provides `a clearance for the clamp 32 when its shank yis received 'in the opening 3`1t`z-of lthe'sleeve 31.; Av center bar carrier 34 is c arriedV within the sleeve-'.31 having an aperture cut inits 'cylin' drical wall in which there is disposed a shank 35 having One oftherobjects of the invention is. to 4provide a t device to be nsednin connection withfglathesmand the vlike which will permit accurate-cutting of-l` cylindrical and taperedlworkpieces.. L z ,"Anoth'erA Qbjectof the .inventionis to' provide a', device forflathes ,and thelikewhichprovides center adjusting meansY for: assuring precise Valignment between head and tailLstoc'k centers...my f t 1 j 'Another `object ofthe .inventiontisg to; provide. agcentering device for lathes andthe like which makes available to the machine operator a pair of tail stock centers and additionally provides quick and ready means for switching from one center to the other center.

Other objects and advantages of the invention will be appreciated on reading the following specification in conjunction with the accompanying drawings, in which Fig. 1 is a plan view of a lathe assembly and the lathe i device attached to its tail stock,

Fig. 2 is an enlarged plan view showingA the llathe device and a portion of the tail stock,

Fig. 3 is a section taken on line 3-3 of Fig. 2,

Fig. 4 is a section taken on line44--4 of Fig. 2, Y

Fig. 5 is a section taken on line 5--5 ofrFig. 2,

Fig. 6, Fig. 7 and Fig. 8 are sections in plane showing successive positions which the center bar and its carrier assume in the process of placing the tail stock center in work holding position,V f Y Y Y Fig. 9. is an end view in section similar to Fig. 4 showing the center holding'carrier in locked position, the broken lines indicating the two extreme positions of the center bar, y' l t Fig. 10 is a detail of the sleeve employed to support the center bar carrier, l

a ilattened hea d 36 the forward end of which is" wider than its opposite side. kAs shown in Fig.- 6, the flattened y head-36 of the shank is received inthe right hand corner of the irregular opening 31a being shouldered thereinso as to prevent effectively any axial movement of the center bar-carrier'34;relative to the cylindrical sleeve 31. 'However,i.as1shownin Fig. 7'the'carrier 34 is adapted to be rotatednelative tothe sleeve allowingthe attenedhead,

of the shank to escape both the shouldered portion of the opening 29 and the clamp 32 thus permitting the carrier 34 to be moved axially forward to a position where the flattenedhead of the shank engages the tapered end of the clamp 32. The clamp contacting edge of the flattened head is biased to complement the taper of the bottom end vof the clamp and extends diagonally from the forward to the rear ends of the head and hence is adapted to positively lock the lcarrier 34 to the sleeve 371 on tightening of the clamp 32. The carrier34 is bored andthe forward end of the carrier extends beyond the housing y28 and the sleeve 31 being provided with a rectan- A gular groove in which there is disposed a center bar 37. A compression spring 38 is disposed in the hollow center of the carrier extending betweenthe plate 30 and the center bar 37 thus giving the carrier land bar a forward bias. An annular plate 39 is bolted to the forward end of theycarrier 34serving to clamp the centerbar in position while allowing it to slide within the'frectangular groove in the carrier when the plateV is loosened., The

center bar has a scaleiMtO the zero point of which normallyr'indicates precise alignment between the worksup- Aporting centers of the head stock and tail stock asV rel v quiredffor cutting cylinders. To the forward sideofthe center bar is attached a center 41 and a center 42 disengageait,

posed at opposite ends thereof. Due to the fact that the plate 39 is easily removed from the carrier 34, the reversal of the center bar for the Vpurpose of bringing a new center into operative position is, facilitated.. .Byl virtue of the provision for permittingfqliick changeover "from one` center tothe other the operator-is ,encouragedto eX amine .the center before and duringthe-.operation of` the machine in; order todetermine that it is .in kvperfect condition.

When the center bar is positioned oithe yzerloqgaoint on the scale 49, the device'is adaptedto cut a taper in the. work piece, the extent of which depends on, the degree of centerA bar displacement from; theV common.

center of the head and tail stocks as-measured-on the.

scaleA 4i). It1 isthus seenv thatthe device lypermitsathe lathe to cutV a precisely defined taper'in .the work. An accurate alignmentbetweenzthe axial centers of the head stock and Atail stockv of, thelathe reqiured to form true` cylinders and to thaty end the tool `providesmeans for adjusting the center 4l, for example, intwo. planesk so as to veffect this'desired alignment when the head stock and `tail stoclc are slightlyvmisaligned. This `adjustment is kafforded the voperator' by virtue ofthe adjustabilityiof the center bar in the forwardrgroove of the carrier 34 and the rotative .mounting of the-sleeve .31 in the housing 28, the latter adjustment being possible on release of the clampingscrew 29a.

WithV a slight modification in, structure, the centering devicel may beapplied to -a gear cutting'` machine. As shown in Fig., l-l, the device is releasably `clamped to a centersupport'bar 43. The plate 30 is, disposed von the right side ofthe tool and the center bar 37-having a single center kle is slidablyl supported on the; left, side of the device. A tensionv spring 38a extends between the plate 30 andI a `stud 45 which is arranged to turn free in -the carrier 34. Thecarrier 34 is oppositely biased with respect tothe sleevel compared toits .biasin'the device above described and the sleeve 31 is reversed so as to enable thefshouldered portion of, its-opening to hold the center Vbar in -open positionl until it is released so `that one of its. centers can come intoY engagement with the work.

Various modifications in the embodiments may be edected by persons skilled in the art without departing from the scope and-principle of the invention as dened` in the following claims.

Whatcis claimed :is:

1., A centering device comprising a housing, rst and second..parallel bores .in said housing a bar Vattachment member secured .in l said Aiirstv bore, Va :sleeve mounted `in 4, said second bore, an irregular opening formed in said sleeve, an 'axially 'and rotatably rslidable center 'bar carrier disposed in said sleeve, said center bar carrier being hollow and having a greater longitudinal length than said housing and sleeve, a flattened head secured to said carrier and extending into the irregular opening in said sleeve, said sleeve having; a. head retaining, shoulder portion formed in the wall of said irregular opening at one end thereof, a clamprextending:throughsaidl housing and into the irregular-'openingofsaid sleeve at the other end oi. said openingfand, beingengageable with.said .flattened head when said carrier is disposed axially inits forward position, `a-fcenter b'armounted inthe forward end of said carrier, a` backing plate -secured to said housing at the rear'end'o'f said secondbore and a forward biasing spring disposed within said hollow carrier and extending between said backing plate and said center bar. 2. Acentering device comprising av housing,.rst and secondparllelbnres in said housing afbarv attachment member securedffin said rstb'ore, a sleeve mounted in said secondbore, an irregular opening formed. in` said sleeve, an axially and rotatably slidable center bar carrier disposed in said sleeve, said4 centerV bar carrier being hollow and having a. greater 'longitudinallength than said housing and" sleeve, said carrier being provided with an aperture which isy disposed communication with said irregular opening in said sleeve, a shank disposedlinthe aperture of, saidr carrier,` a flattened headportion extendingpradially `from said shankY into the irregular opening:

oflsaid sleeve, 'said sleeve having a shank retaining, shoulder portionformedfin the Wall'of said irregular opening at'one end thereof, aclamp extending through saidk housing'andfinto the 'irregular opening Vof said sleeve at theother end offsaid :opening and'being engageable, with the 'ilattenedhead" of said IshankA whenV said .carrier `i`s dis,- po'sed axi'a'llyfinitsforward'position, a center'bar mounted inthe forward'end oisaid carrier, a'backing plate secured tosaidhousing at .the rear endv of said second'bore, andl a 'forward' biasing spring disposed 'within said lhollow carri'erfand, extendingjbetween saidbacking plate andfsaid center bar.r

`References'Cte'd'in the file ofthis patent UNITED vSTATESY PATENTS 1,226,825 Stewart May'ZZ,v 1.91.7'v .L3-911,034 f i Williams- S,ept.v20, ,1.921 12,390,627' -Y Truba-et zal. Dec. 11, 1945- l2,'564,256 Henderhanm L -Aug. 14,1951 2,724,302 Poorman Nov. 22.,v 13955` 800,046JA j'Kluclr Iuly 23, 11957 

